EP0631839A1 - Procedure for the realization of an aluminium layer structure on a substrate of alumium nitride - Google Patents

Procedure for the realization of an aluminium layer structure on a substrate of alumium nitride Download PDF

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Publication number
EP0631839A1
EP0631839A1 EP94401432A EP94401432A EP0631839A1 EP 0631839 A1 EP0631839 A1 EP 0631839A1 EP 94401432 A EP94401432 A EP 94401432A EP 94401432 A EP94401432 A EP 94401432A EP 0631839 A1 EP0631839 A1 EP 0631839A1
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EP
European Patent Office
Prior art keywords
aluminized
substrate
laser
areas
nitride
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP94401432A
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German (de)
French (fr)
Inventor
Luc Vergnaud
Olivier Kirmann
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Alcatel Lucent SAS
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Alcatel SA
Alcatel Alsthom Compagnie Generale dElectricite
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Publication of EP0631839A1 publication Critical patent/EP0631839A1/en
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K26/00—Working by laser beam, e.g. welding, cutting or boring
    • B23K26/02—Positioning or observing the workpiece, e.g. with respect to the point of impact; Aligning, aiming or focusing the laser beam
    • B23K26/06—Shaping the laser beam, e.g. by masks or multi-focusing
    • B23K26/064—Shaping the laser beam, e.g. by masks or multi-focusing by means of optical elements, e.g. lenses, mirrors or prisms
    • B23K26/066—Shaping the laser beam, e.g. by masks or multi-focusing by means of optical elements, e.g. lenses, mirrors or prisms by using masks
    • B23K26/0661—Shaping the laser beam, e.g. by masks or multi-focusing by means of optical elements, e.g. lenses, mirrors or prisms by using masks disposed on the workpiece
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K26/00—Working by laser beam, e.g. welding, cutting or boring
    • B23K26/18—Working by laser beam, e.g. welding, cutting or boring using absorbing layers on the workpiece, e.g. for marking or protecting purposes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41M—PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING
    • B41M5/00—Duplicating or marking methods; Sheet materials for use therein
    • B41M5/24—Ablative recording, e.g. by burning marks; Spark recording
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer
    • H01L21/48—Manufacture or treatment of parts, e.g. containers, prior to assembly of the devices, using processes not provided for in a single one of the subgroups H01L21/06 - H01L21/326
    • H01L21/4814—Conductive parts
    • H01L21/4846—Leads on or in insulating or insulated substrates, e.g. metallisation
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K3/00—Apparatus or processes for manufacturing printed circuits
    • H05K3/10—Apparatus or processes for manufacturing printed circuits in which conductive material is applied to the insulating support in such a manner as to form the desired conductive pattern
    • H05K3/105—Apparatus or processes for manufacturing printed circuits in which conductive material is applied to the insulating support in such a manner as to form the desired conductive pattern by conversion of non-conductive material on or in the support into conductive material, e.g. by using an energy beam

Definitions

  • the present invention relates to a process for producing aluminized structures on an aluminum nitride substrate.
  • the aluminum nitride substrate is an electrically insulating and heat conductive ceramic.
  • the function of such a substrate is in particular to dissipate the heat coming from the electronic components which it supports. It is necessary to be able to produce electrically conductive structures on this substrate allowing the interconnection of the various electronic components.
  • These structures can be, for example, holes, opening or not, of various shapes (circular, rectangular, etc.) or else patterns: contact pads, conductive lines, and the like.
  • the holes for example are first drilled and then filled with a conductive substance (lacquer or conductive ink, etc.).
  • a conductive substance lacquer or conductive ink, etc.
  • the surface is metallized beforehand by vacuum deposition, then the patterns are produced by known techniques for forming electrically conductive structures.
  • the photolithographic etching technique has several drawbacks.
  • the operations are numerous and generate significant quantities of substances to be reprocessed, in particular solvents.
  • the metallization operation is very difficult to perform on the walls and at the bottom of the hole and the adhesion of the deposit obtained is poor.
  • Another known method is screen printing, which consists of depositing an ink containing the conductive substance by passing it through a mask using a squeegee. By baking, the desired conductive pattern is obtained.
  • the deposit made by this method is thick (greater than 10 ⁇ m), which makes metallization of a small diameter hole very difficult to achieve.
  • the present invention relates to a method for producing conductive structures, in particular in small holes, which is easier to implement than the known methods and whose regularity and adhesion characteristics of the conductive structure obtained are improved.
  • the object of the present invention is a method of producing aluminized structures on predetermined areas of an aluminum nitride substrate. These areas are irradiated by a UV laser operating in pulse mode at a wavelength between 193nm and 351nm, the energy density on the areas being greater than or equal to 500mJ / cm2. The maximum energy density is only limited by the type of laser used.
  • the aluminum and nitrogen contained in the material evaporate. Then the aluminum condenses on the surface to create an electrically conductive layer in the interaction zone UV-aluminum nitride beam limited by the reduced image of a mask representing the structure to be produced.
  • the mask has the advantage of allowing, on the one hand, faster production of complex patterns, and on the other hand obtaining patterns with sharp edges by limiting the beam to its most energetic.
  • the irradiation is preferably carried out in a non-oxidizing atmosphere although an electrically conductive structure can be obtained in ambient air.
  • an electrically conductive structure can be obtained in ambient air.
  • aluminum risks forming alumina on the surface, which reduces the quality of the deposit.
  • the irradiation is carried out under vacuum.
  • the irradiation is carried out under neutral gas, such as argon or helium.
  • the frequency of repetition of the laser impacts depends on the source used, for example 1Hz to 250Hz, but frequencies above 250Hz also allow the formation of an electrically conductive layer.
  • the speed of movement of the beam depends directly on this frequency.
  • the speed of movement of said laser is chosen so that the impact recovery rate is greater than 10%.
  • the successive impacts overlap so that there is continuity in the pattern.
  • the method according to the present invention has the advantage of making it possible to produce an aluminized structure in a single operation.
  • the process does not require the addition of products; it does not produce harmful gases or waste (solvent, acid, etc.) to be reprocessed, which makes it particularly economical.
  • the present invention also relates to an aluminized structure obtained by this process, comprising a aluminum layer with a thickness of less than 1 ⁇ m, generally of the order of a few tenths of a micron.
  • the aluminized structure has the shape of a hole with a diameter between 1 ⁇ m and 1 mm.
  • the method makes it possible to produce electrically conductive holes, whether through or not, in which a layer of aluminum is regularly deposited on the walls and the bottom of the hole drilled by the laser.
  • the aluminum layer thus formed can serve directly as an electrically conductive layer and thus receive electronic components.
  • the aluminized structure is also covered with an electrolytic metal deposit. If the metal required is not aluminum, the aluminized surfaces will behave like activated surfaces on which an electrolytic deposition will preferably take place.
  • the main advantage of the aluminized structure produced according to the present process is that the aluminum layer thus formed has an excellent adhesion which cannot be obtained with known processes.
  • this process it is possible to produce a complex aluminized structure with a precision in the dimension of the pattern of the order of 1%.
  • FIG. 1 consists in first depositing by evaporation a conductive substance 2 (gold, silver, copper, ...) on the substrate 1, then the whole is covered with a photosensitive resin 3. We proceed then on the exposure of the resin by a UV lamp through a mask representing the negative of the pattern on a scale 1. The exposed resin 4 is then removed by rinsing, and in this zone the part 5 of the conductive film which has become visible is eliminated by chemical dissolution. Finally the rinsing of the substrate makes it possible to remove the remaining resin while allowing the desired conductive pattern to appear.
  • a conductive substance 2 gold, silver, copper, ...)
  • a variant of this method represented in FIG. 2 consists in first depositing the resin 3 which is exposed through a mask. After removal of the insolated resin 4, the conductive substance 2 is deposited by evaporation. A final rinse removes the remaining resin, revealing the desired conductive pattern.
  • FIG. 3 The installation for producing aluminized structures on an aluminum nitride substrate according to the present invention is shown diagrammatically in FIG. 3.
  • the production of these electrically conductive structures requires the use of a UV laser 10 operating in pulse mode at one wavelength between 193 nm and 351 nm, of a mask 11 representing an enlargement of the structure to be produced, of an optical system 12 for projecting the mask 11, and of an enclosure 13 for working in a controlled atmosphere.
  • the laser beam 14 transported by a set of mirrors reaches the mask 11.
  • the part of the diaphragmed beam is processed by the optical system 12 which reconstructs the image of the mask 11 on the substrate 15 of aluminum nitride on a reduced scale, d a factor 2 to 200, which depends on the setting of the optical system 12.
  • the pattern to be produced is projected on scale 1 on the substrate 15.
  • An installation similar to that described above but not comprising a mask is used for producing a conductive line on an aluminum nitride substrate.
  • the irradiation is carried out under a neutral atmosphere, the substrate being placed under argon.
  • the laser employed delivers a pulse frequency of the order of 100 Hz, which allows a linear processing speed of the substrate of 60 mm / min while preserving the continuity of the pattern.
  • the energy density reached on the irradiated areas is 10J / cm2.
  • the thickness of the aluminum layer is approximately 0.5 ⁇ m.
  • the conductive line obtained is characterized by its resistance which is 30 ⁇ / cm.
  • An installation similar to that described above but comprising a mask representing a disk is used for the production of a metallized circular hole on an aluminum nitride substrate.
  • the irradiation is carried out in ambient air.
  • the laser employed delivers a pulse frequency of the order of 10 Hz, which allows a substrate ablation speed of 25 ⁇ m / min.
  • the energy density reached on the irradiated areas is 13J / cm2.
  • the thickness of the aluminum layer is approximately 0.5 ⁇ m.
  • the metallized hole obtained has a diameter of approximately 250 ⁇ m. It is characterized by its resistance which is 100 ⁇ / cm.

Abstract

The subject of the present invention is a process for producing aluminized structures on predetermined areas of a substrate made of aluminium nitride, characterised in that the said areas are irradiated by a UV laser (10) operating in pulse mode at a wavelength between 193 nm and 351 nm, the energy density on the said areas being greater than or equal to 500 mJ/cm<2>. The subject of the present invention is also an aluminized structure obtained by the preceding process, this structure comprising a layer of aluminium less than 1 mu m in thickness. <IMAGE>

Description

La présente invention concerne un procédé de réalisation de structures aluminisées sur un substrat de nitrure d'aluminium.The present invention relates to a process for producing aluminized structures on an aluminum nitride substrate.

Le substrat de nitrure d'aluminium est une céramique électriquement isolante et bonne conductrice de la chaleur. Un tel substrat a notamment pour fonction de dissiper la chaleur provenant des composants électroniques qu'il supporte. Il est nécessaire de pouvoir réaliser sur ce substrat des structures électriquement conductrices permettant l'interconnexion des différents composants électroniques.The aluminum nitride substrate is an electrically insulating and heat conductive ceramic. The function of such a substrate is in particular to dissipate the heat coming from the electronic components which it supports. It is necessary to be able to produce electrically conductive structures on this substrate allowing the interconnection of the various electronic components.

Ces structures peuvent être par exemple des trous, débouchants ou non, de formes diverses (circulaire, rectangulaire, etc...) ou bien des motifs : plots de contact, lignes conductrices, et autres. Les trous par exemple sont d'abord percés puis remplis d'une substance conductrice (laque ou encre conductrice, etc...). Dans le cas des motifs, la surface est préalablement métallisée par dépôt sous vide, puis les motifs sont réalisés par des techniques connues de formation de structures électriquement conductrices.These structures can be, for example, holes, opening or not, of various shapes (circular, rectangular, etc.) or else patterns: contact pads, conductive lines, and the like. The holes for example are first drilled and then filled with a conductive substance (lacquer or conductive ink, etc.). In the case of patterns, the surface is metallized beforehand by vacuum deposition, then the patterns are produced by known techniques for forming electrically conductive structures.

L'une de ces techniques est la gravure photolithographique décrite par D.M. ALLEN dans son livre: "The principles and practice of photochemical machining and photoetching." (Ed.A.HILGER, Bristol, 1986). Cette méthode consiste à faire apparaître le motif conducteur souhaité en éliminant une résine photosensible après insolation par une lampe U.V. à travers un masque reproduisant ce motif.One of these techniques is photolithographic engraving described by D.M. ALLEN in his book: "The principles and practice of photochemical machining and photoetching." (Ed.A. HILGER, Bristol, 1986). This method consists in making the desired conductive pattern appear by eliminating a photosensitive resin after exposure by a UV lamp through a mask reproducing this pattern.

L'article de K. OGAWA et al. "Advanced KrF excimer laser lithography for half micron devices" paru en 1988 dans "Laser processes for microelectronic applications." (Electrochem.Soc., Pennington) décrit un perfectionnement de cette méthode appelée photolithographie assistée par laser. Il consiste, pour effectuer l'insolation de la résine, à utiliser une source laser et un système optique projetant le motif souhaité sur le substrat à une échelle réduite.The article by K. OGAWA et al. "Advanced KrF excimer laser lithography for half micron devices" published in 1988 in "Laser processes for microelectronic applications." (Electrochem.Soc., Pennington) describes a development of this method called laser-assisted photolithography. It consists, to perform the insolation of the resin, using a laser source and an optical system projecting the desired pattern on the substrate on a reduced scale.

La technique de gravure photolithographique présentent plusieurs inconvénients. Les opérations sont nombreuses et génèrent des quantité importantes de substances à retraiter, en particulier des solvants. De plus dans le cas d'un trou, l'opération de métallisation est très difficile à réaliser sur les parois et au fond du trou et l'adhérence du dépôt obtenu est médiocre.The photolithographic etching technique has several drawbacks. The operations are numerous and generate significant quantities of substances to be reprocessed, in particular solvents. In addition in the case of a hole, the metallization operation is very difficult to perform on the walls and at the bottom of the hole and the adhesion of the deposit obtained is poor.

Une autre méthode connue est la sérigraphie qui consiste à déposer une encre contenant la substance conductrice en la faisant passer à travers un masque à l'aide d'une raclette. Par cuisson, on obtient le motif conducteur souhaité. Le dépôt effectué par cette méthode est épais (supérieur à 10µm), ce qui rend la métallisation d'un trou de faible diamètre très difficile à réaliser.Another known method is screen printing, which consists of depositing an ink containing the conductive substance by passing it through a mask using a squeegee. By baking, the desired conductive pattern is obtained. The deposit made by this method is thick (greater than 10 μm), which makes metallization of a small diameter hole very difficult to achieve.

La présente invention concerne un procédé de réalisation de structures conductrices, en particulier dans des trous de faibles dimensions, de mise en oeuvre plus facile que les procédé connus et dont les caractéristiques de régularité et d'adhérence de la structure conductrice obtenue sont améliorées.The present invention relates to a method for producing conductive structures, in particular in small holes, which is easier to implement than the known methods and whose regularity and adhesion characteristics of the conductive structure obtained are improved.

L'objet de la présente invention est un procédé de réalisation de structures aluminisées sur des zones prédéterminées d'un substrat de nitrure d'aluminium. Ces zones sont irradiées par un laser U.V. fonctionnant en mode impulsionnel à une longueur d'onde comprise entre 193nm et 351nm, la densité d'énergie sur les zones étant supérieure ou égale à 500mJ/cm². Le maximum de densité d'énergie n'est limitée que par le type de laser utilisé.The object of the present invention is a method of producing aluminized structures on predetermined areas of an aluminum nitride substrate. These areas are irradiated by a UV laser operating in pulse mode at a wavelength between 193nm and 351nm, the energy density on the areas being greater than or equal to 500mJ / cm². The maximum energy density is only limited by the type of laser used.

Lorsque la densité d'énergie sur le nitrure d'aluminium atteint 500mJ/cm², l'aluminium et l'azote contenus dans le matériau s'évaporent. Puis l'aluminium se recondense sur la surface pour créer une couche électriquement conductrice dans la zone d'interaction faisceau U.V.-nitrure d'aluminium limitée par l'image réduite d'un masque représentant la structure à réaliser. Bien qu'il ne soit pas indispensable, le masque a pour avantage de permettre d'une part la réalisation plus rapide de motifs complexes, et d'autres part l'obtention de motifs à bords francs en limitant le faisceau à son domaine le plus énergétique.When the energy density on the aluminum nitride reaches 500mJ / cm², the aluminum and nitrogen contained in the material evaporate. Then the aluminum condenses on the surface to create an electrically conductive layer in the interaction zone UV-aluminum nitride beam limited by the reduced image of a mask representing the structure to be produced. Although it is not essential, the mask has the advantage of allowing, on the one hand, faster production of complex patterns, and on the other hand obtaining patterns with sharp edges by limiting the beam to its most energetic.

L'irradiation est réalisée de préférence en atmosphère non oxydante bien qu'une structure électriquement conductrice puisse être obtenue à l'air ambiant. En présence d'oxygène, l'aluminium risque de former de l'alumine en surface ce qui diminue la qualité du dépôt.The irradiation is preferably carried out in a non-oxidizing atmosphere although an electrically conductive structure can be obtained in ambient air. In the presence of oxygen, aluminum risks forming alumina on the surface, which reduces the quality of the deposit.

Selon une variante préférentielle de mise en oeuvre du procédé, l'irradiation est effectuée sous vide.According to a preferred variant of implementation of the method, the irradiation is carried out under vacuum.

Selon une autre variante de mise en oeuvre du procédé, l'irradiation est effectuée sous gaz neutre, comme l'argon ou l'hélium.According to another variant implementation of the method, the irradiation is carried out under neutral gas, such as argon or helium.

La fréquence de répétition des impacts du laser dépend de la source utilisée, par exemple 1Hz à 250Hz, mais des fréquences supérieures à 250Hz permettent aussi la formation d'une couche électriquement conductrice. La vitesse de déplacement du faisceau dépend directement de cette fréquence.The frequency of repetition of the laser impacts depends on the source used, for example 1Hz to 250Hz, but frequencies above 250Hz also allow the formation of an electrically conductive layer. The speed of movement of the beam depends directly on this frequency.

De préférence, la vitesse de déplacement dudit laser est choisie de telle sorte que le taux de recouvrement des impacts soit supérieur à 10%. Pour la formation de lignes conductrices, il faut que les impacts successifs se chevauchent pour qu'il y ait continuité dans le motif.Preferably, the speed of movement of said laser is chosen so that the impact recovery rate is greater than 10%. For the formation of conductive lines, it is necessary that the successive impacts overlap so that there is continuity in the pattern.

Le procédé selon la présente invention a pour avantage de permettre de réaliser une structure aluminisée en une seule opération. Le procédé ne nécessite pas l'ajout de produits; il ne produit pas de dégagement de gaz nocifs ni de déchets (solvant, acide, ...) à retraiter, ce qui le rend particulièrement économique.The method according to the present invention has the advantage of making it possible to produce an aluminized structure in a single operation. The process does not require the addition of products; it does not produce harmful gases or waste (solvent, acid, etc.) to be reprocessed, which makes it particularly economical.

La présente invention a également pour objet une structure aluminisée obtenue par ce procédé, comportant une couche d'aluminium d'épaisseur inférieure à 1µm, en général de l'ordre de quelques dixièmes de microns.The present invention also relates to an aluminized structure obtained by this process, comprising a aluminum layer with a thickness of less than 1 μm, generally of the order of a few tenths of a micron.

Selon une variante de réalisation, la structure aluminisée a la forme d'un trou de diamètre compris entre 1µm et 1mm. Le procédé permet de réaliser des trous, débouchants ou non et électriquement conducteurs dans lesquels une couche d'aluminium est régulièrement déposée sur les parois et le fond du trou percé par le laser. La couche d'aluminium ainsi formée peut servir directement de couche électriquement conductrice et ainsi recevoir des composants électroniques.According to an alternative embodiment, the aluminized structure has the shape of a hole with a diameter between 1 μm and 1 mm. The method makes it possible to produce electrically conductive holes, whether through or not, in which a layer of aluminum is regularly deposited on the walls and the bottom of the hole drilled by the laser. The aluminum layer thus formed can serve directly as an electrically conductive layer and thus receive electronic components.

Selon une autre variante de réalisation, la structure aluminisée est en outre recouverte d'un dépôt de métal électrolytique. Si le métal requis n'est pas l'aluminium, les surfaces aluminisées se comporteront comme des surfaces activées sur lesquels un dépôt électrolytique se fera préférentiellement.According to another alternative embodiment, the aluminized structure is also covered with an electrolytic metal deposit. If the metal required is not aluminum, the aluminized surfaces will behave like activated surfaces on which an electrolytic deposition will preferably take place.

Le principal avantage de la structure aluminisée réalisée selon le présent procédé est que la couche d'aluminium ainsi constituée a une excellente adhérence qui ne peut pas être obtenue avec les procédés connus. De plus par ce procédé il est possible de réaliser une structure aluminisée complexe avec une précision dans la dimension du motif de l'ordre de 1%.The main advantage of the aluminized structure produced according to the present process is that the aluminum layer thus formed has an excellent adhesion which cannot be obtained with known processes. In addition, by this process it is possible to produce a complex aluminized structure with a precision in the dimension of the pattern of the order of 1%.

D'autres caractéristiques et avantages de la présente invention apparaitront au cours de la description et à la lecture des exemples suivants de modes de réalisation, donnés bien entendu à titre illustratif et non limitatif, et dans le dessin annexé dans lequel:

  • la figure 1 montre schématiquement le procédé de l'art antérieur,
  • la figure 2, analogue à la figure 1, donne une variante du procédé de l'art antérieur,
  • la figure 3 représente le procédé selon la présente invention.
Other characteristics and advantages of the present invention will appear during the description and on reading the following examples of embodiments, given of course by way of illustration and not limitation, and in the appended drawing in which:
  • FIG. 1 schematically shows the method of the prior art,
  • FIG. 2, similar to FIG. 1, gives a variant of the method of the prior art,
  • FIG. 3 represents the method according to the present invention.

Selon l'art antérieur, l'une des techniques habituellement employée est la gravure photolithographique. Cette méthode représentée par la figure 1 consiste à déposer d'abord par évaporation une substance conductrice 2 (or, argent, cuivre, ...) sur le substrat 1, puis l'ensemble est recouvert d'une résine photosensible 3. On procède alors à l'insolation de la résine par une lampe U.V. à travers un masque représentant le négatif du motif à l'échelle 1. La résine insolée 4 est ensuite enlevée par rinçage, et dans cette zone la partie 5 du film conducteur devenue apparente est éliminée par dissolution chimique. Enfin le rinçage du substrat permet d'enlever la résine restante en laissant apparaître le motif conducteur souhaité.According to the prior art, one of the techniques usually used is photolithographic etching. This method represented by FIG. 1 consists in first depositing by evaporation a conductive substance 2 (gold, silver, copper, ...) on the substrate 1, then the whole is covered with a photosensitive resin 3. We proceed then on the exposure of the resin by a UV lamp through a mask representing the negative of the pattern on a scale 1. The exposed resin 4 is then removed by rinsing, and in this zone the part 5 of the conductive film which has become visible is eliminated by chemical dissolution. Finally the rinsing of the substrate makes it possible to remove the remaining resin while allowing the desired conductive pattern to appear.

Une variante de cette méthode représentée sur la figure 2 consiste à déposer en premier lieu la résine 3 qui est insolée à travers un masque. Après élimination de la résine insolée 4, la substance conductrice 2 est déposée par évaporation. Un dernier rinçage enlève la résine restante en laissant apparaître le motif conducteur souhaité.A variant of this method represented in FIG. 2 consists in first depositing the resin 3 which is exposed through a mask. After removal of the insolated resin 4, the conductive substance 2 is deposited by evaporation. A final rinse removes the remaining resin, revealing the desired conductive pattern.

L'installation de réalisation de structures aluminisées sur un substrat de nitrure d'aluminium selon la présente invention est schématisée sur la figure 3. La réalisation de ces structures électriquement conductrices nécessite l'emploi d'un laser U.V. 10 fonctionnant en mode impulsionnel à une longueur d'onde comprise entre 193nm et 351nm, d'un masque 11 représentant un agrandissement de la structure à réaliser, d'un système optique 12 de projection du masque 11, et d'une enceinte 13 pour travailler en atmosphère controlée. Le faisceau laser 14 transporté par un jeu de miroirs atteint le masque 11. La partie du faisceau diaphragmée est traitée par le système optique 12 qui reconstruit l'image du masque 11 sur le substrat 15 de nitrure d'aluminium à une échelle réduite, d'un facteur 2 à 200, qui dépend du réglage du système optique 12. Le motif à réaliser se trouve projeté à l'échelle 1 sur le substrat 15.The installation for producing aluminized structures on an aluminum nitride substrate according to the present invention is shown diagrammatically in FIG. 3. The production of these electrically conductive structures requires the use of a UV laser 10 operating in pulse mode at one wavelength between 193 nm and 351 nm, of a mask 11 representing an enlargement of the structure to be produced, of an optical system 12 for projecting the mask 11, and of an enclosure 13 for working in a controlled atmosphere. The laser beam 14 transported by a set of mirrors reaches the mask 11. The part of the diaphragmed beam is processed by the optical system 12 which reconstructs the image of the mask 11 on the substrate 15 of aluminum nitride on a reduced scale, d a factor 2 to 200, which depends on the setting of the optical system 12. The pattern to be produced is projected on scale 1 on the substrate 15.

EXEMPLE 1EXAMPLE 1

Une installation analogue à celle décrite précédemment mais ne comportant pas de masque est utilisée pour la réalisation d'une ligne conductrice sur un substrat de nitrure d'aluminium. L'irradiation est effectuée sous atmosphère neutre, le substrat étant placé sous argon. Le laser employé délivre une fréquence d'impulsions de l'ordre de 100Hz, ce qui permet une vitesse linéaire de traitement du substrat de 60mm/mn tout en préservant la continuité du motif. La densité d'énergie atteinte sur les zones irradiées est de 10J/cm². L'épaisseur de la couche d'aluminium est d'environ 0,5µm. La ligne conductrice obtenue est caractérisée par sa résistance qui est de 30Ω/cm.An installation similar to that described above but not comprising a mask is used for producing a conductive line on an aluminum nitride substrate. The irradiation is carried out under a neutral atmosphere, the substrate being placed under argon. The laser employed delivers a pulse frequency of the order of 100 Hz, which allows a linear processing speed of the substrate of 60 mm / min while preserving the continuity of the pattern. The energy density reached on the irradiated areas is 10J / cm². The thickness of the aluminum layer is approximately 0.5 µm. The conductive line obtained is characterized by its resistance which is 30Ω / cm.

EXEMPLE 2EXAMPLE 2

Une installation analogue à celle décrite précédemment mais comportant un masque représentant un disque est utilisée pour la réalisation d'un trou circulaire métallisé sur un substrat de nitrure d'aluminium. L'irradiation est effectuée à l'air ambiant. Le laser employé délivre une fréquence d'impulsions de l'ordre de 10Hz, ce qui permet une vitesse d'ablation du substrat de 25µm/mn. La densité d'énergie atteinte sur les zones irradiées est de 13J/cm². L'épaisseur de la couche d'aluminium est d'environ 0,5µm. Le trou métallisé obtenu a un diamètre d'environ 250µm. Il est caractérisée par sa résistance qui est de 100Ω/cm.An installation similar to that described above but comprising a mask representing a disk is used for the production of a metallized circular hole on an aluminum nitride substrate. The irradiation is carried out in ambient air. The laser employed delivers a pulse frequency of the order of 10 Hz, which allows a substrate ablation speed of 25 μm / min. The energy density reached on the irradiated areas is 13J / cm². The thickness of the aluminum layer is approximately 0.5 µm. The metallized hole obtained has a diameter of approximately 250 μm. It is characterized by its resistance which is 100Ω / cm.

Bien entendu la présente invention n'est pas limitée aux modes de réalisation décrits et représentés, mais elle est suceptible de nombreuses variantes accessibles à l'homme de l'art sans que l'on ne s'écarte de l'esprit de l'invention.Of course, the present invention is not limited to the embodiments described and shown, but it is susceptible of numerous variants accessible to those skilled in the art without departing from the spirit of the invention.

Claims (7)

1./ Procédé de réalisation de structures aluminisées sur des zones prédéterminées d'un substrat de nitrure d'aluminium, caractérisé par le fait que lesdites zones sont irradiées par un laser U.V. fonctionnant en mode impulsionnel à une longueur d'onde comprise entre 193nm et 351nm, la densité d'énergie sur lesdites zones étant supérieure ou égale à 500mJ/cm². 1. / A method of producing aluminized structures on predetermined areas of an aluminum nitride substrate, characterized in that said areas are irradiated by a UV laser operating in pulse mode at a wavelength between 193 nm and 351nm, the energy density on said zones being greater than or equal to 500mJ / cm². 2./ Procédé selon la revendication 1, caractérisé par le fait que l'irradiation est effectuée sous vide. 2. / A method according to claim 1, characterized in that the irradiation is carried out under vacuum. 3./ Procédé selon la revendication 1, caractérisé par le fait que l'irradiation est effectuée sous gaz neutre. 3. / A method according to claim 1, characterized in that the irradiation is carried out under neutral gas. 4./ Procédé selon l'une des revendications précédentes, caractérisé par le fait que la vitesse de déplacement dudit laser est choisie de telle sorte que le taux de recouvrement des impacts soit supérieur à 10%. 4. / Method according to one of the preceding claims, characterized in that the speed of movement of said laser is chosen so that the impact recovery rate is greater than 10%. 5./ Structure aluminisée obtenue par le procédé selon l'une des revendications précédentes, caractérisée par le fait que ladite structure comporte une couche d'aluminium d'épaisseur inférieure à 1µm. 5. / aluminized structure obtained by the method according to one of the preceding claims, characterized in that said structure comprises an aluminum layer of thickness less than 1 µm. 6./ Structure aluminisée obtenue par le procédé selon l'une des revendications précédentes, caractérisée par le fait que ladite structure a la forme d'un trou de diamètre compris entre 1µm et 1mm. 6. / aluminized structure obtained by the method according to one of the preceding claims, characterized in that said structure has the shape of a hole with a diameter between 1 µm and 1 mm. 7./ Structure aluminisée obtenue par le procédé selon l'une des revendications précédentes, caractérisée par le fait que ladite structure est en outre recouverte d'un dépôt de métal électrolytique. 7. / aluminized structure obtained by the method according to one of the preceding claims, characterized in that said structure is also covered with an electrolytic metal deposit.
EP94401432A 1993-06-28 1994-06-24 Procedure for the realization of an aluminium layer structure on a substrate of alumium nitride Withdrawn EP0631839A1 (en)

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JPS63298400A (en) * 1987-05-29 1988-12-06 松下電器産業株式会社 Formant extractor

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Publication number Priority date Publication date Assignee Title
JPS54149617A (en) * 1978-05-16 1979-11-24 Tomoegawa Paper Co Ltd Light heat recording material
EP0121150A1 (en) * 1983-03-31 1984-10-10 Carl Baasel Lasertechnik GmbH Piece of aluminium material, preferably an aluminium plate, and process for producing the same

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS54149617A (en) * 1978-05-16 1979-11-24 Tomoegawa Paper Co Ltd Light heat recording material
EP0121150A1 (en) * 1983-03-31 1984-10-10 Carl Baasel Lasertechnik GmbH Piece of aluminium material, preferably an aluminium plate, and process for producing the same

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
DATABASE WPI Week 8002, Derwent World Patents Index; AN 80-02419C *

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CA2126807A1 (en) 1994-12-29
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JPH0758436A (en) 1995-03-03
FI943088A (en) 1994-12-29

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